Single-layer projected capacitive touch panel and method of manufacturing the same

ABSTRACT

A single-layer projected capacitive touch panel has a glass cover, a touch sensing circuit layer, an insulating ink layer, a conductive wire layer, an insulator layer, a conductive glue layer and a flexible printed circuit (FPC) board. The touch sensing circuit layer, the insulating ink layer, the conductive wire layer, the insulator layer and the conductive glue layer are mounted on a circuit surface of the glass cover in sequence. The insulating ink layer covers the touch sensing circuit layer and has multiple through slots. Each through slot is filled with an electric conductor. The FPC is fastened on the conductive wire layer by a conductive glue layer. Therefore, the touch panel of the present invention is thinner, provides better penetrability and costs less than conventional projected capacitive touch panels.

This application is a continuation application of Ser. No. 12/661,787,filed Mar. 24, 2010, which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a single-layer projected capacitivetouch panel and a method for manufacturing the same, and moreparticularly to a single-layer projected capacitive touch panel in Whicha single glass layer is required, and a method of manufacturing thesame.

2. Description of the Related Art

The advancement of touch panel technology has resulted in many consumerelectronic products such as personal digital assistant (PDA), globalpositioning systems (GPS) and the like being equipped with touch panels.

Before iPhone™ was released, resistive touch panels were generally usedon small size portable electronic devices because they had sufficientlymatured to keep costs low and be reliable. However, resistive touchpanels cannot track more than one finger so resistive touch panelscannot resolve multipoint touches. After iPhone™ was announced,projected capacitive touch panels became desirable because it enablesmultipoint touch.

With reference to FIG. 5, a conventional projected capacitive touchpanel comprises a glass base (91), a touch sensing, circuit layer (92),a conductive wire layer (93), an insulator layer (94), a conductive gluelayer (95) a flexible printed circuit (FPC) board (96), an optical gluelayer (97) and a glass cover (98). The glass base (91) has a circuitsurface (911). The touch sensing circuit layer (92) is composed ofsingle-layer touch sensing circuits, and the touch sensing circuit layer(92) and the conductive wire layer (93) are formed on the circuitsurface (911) of the glass base (91) and are electronically connectedtogether. The insulator layer (94) is formed on and covers theconductive wire layer (93), and the insulator layer (94) has a breach topartially expose the conductive wire layer (93). The conductive gluelayer (95) is formed on the breath of the insulator layer (94) to coverthe exposed conductive wire layer (93). The FPC board (96) is adhered tothe conductive glue layer (95) and electronically to the conductive wirelayer (93) via the conductive glue layer (95). The optical glue layer(97) is formed on the touch sensing circuit layer (92) and the insulatorlayer (94). The glass cover (98) has an operating surface (981) and anadhering surface (982). The adhering surface (982) of the glass cover(98) is adhered to the optical glue layer (97). The operating surface(981) of the glass cover (98) functions either as a touch surface or aprotection cover to protect the touch sensing circuit layer (92), theconductive wire layer (93) and the conductive glue layer (95) on theglass base (91).

Since the conventional projected capacitive touch panel requires twoglasses (91, 98), and the two glasses (91, 98) are fixed by the opticalglue layer (97), the conventional projected capacitive touch panel hasthe disadvantages.

1. The optical glue layer (97) is positioned between the glass base (91)and the glass cover (98) so reduces penetrability of the conventionalprojected capacitive touch panel.

2. Adhering the two glasses (91, 98) requires great accuracy soaffecting manufacturing yield rate. Current techniques cannot providehigh accuracy of adhering the glasses for increased yield rate ofmanufacturing the conventional projected capacitive touch panel.

3. The insulator layer (94) and the FPC board (97) may be visible fromthe operating surface (981) of the glass cover (98) because the opticalglue layer (97) is transparent. When installing the conventionalprojected capacitive touch panel on an electronic device, a casing onthe electronic device must be designed to have opaque rims to cover theinsulator layer (94) and the FPC board (97). However, such designlimitation restricts application and in also requires accurate machiningso further raising costs and reducing manufacturing yield.

To overcome the shortcomings, the present invention provides asingle-layer projected capacitive touch panel and a method ofmanufacturing the same to mitigate or obviate the aforementionedproblems.

SUMMARY OF THE INVENTION

The main objective of the invention is to provide a projected capacitivetouch panel in which a single glass layer is required, and a method ofmanufacturing the same.

The projected touch panel in accordance with the embodiment of thepresent invention comprises a glass cover, a touch sensing circuitlayer, an insulating ink layer, a conductive wire layer, an insulatorlayer, a conductive glue layer and a flexible printed circuit (FPC)board. The touch sensing circuit layer, the insulating ink layer, theconductive wire layer, the insulator layer and the conductive glue layerare mounted on a circuit surface of the glass cover in sequence. Theinsulating ink layer covers edges of the touch sensing circuit layer andhas multiple through slots. Each through slot is filled with an electricconductor to electronically connect the conductive wire layer with thetouch sensing circuit layer. The FPC is fastened on and electronicallyconnects to the conductive wire layer by a conductive glue layer.

The method in accordance with the embodiment of the present inventioncomprises steps of:

-   -   providing a glass parent board divided into multiple glass        covers, and each glass cover having an operating surface and a        circuit surface;

forming touch sensing layers respectively on the glass covers, and eachtouch sensing layer partially formed on the circuit surface of eachglass cover, having multiple edges and composed of single-layer touchsensing circuits;

forming insulating ink layers respectively on the touch sensing circuitlayers, and each insulating ink layer formed on and near the edges ofeach touch sensing circuit layer to partially cover the touch sensingcircuit layer, and each insulating ink layer having multiple throughslots corresponding to and exposing the touch sensing circuit layercovered by the insulating ink layer;

forming electric conductors in the through slots;

-   -   forming conductive wire layers respectively on the insulating        ink layers to contact with the electric conductors so the        conductive wire layers electronically connect respectively to        the touch sensing circuit layers via the electric conductors;

forming insulator layers respectively on the conductive wire layers, andeach insulator layer having a breach to expose partial conductive wirelayer;

separating the glass parent board into multiple glass covers;

installing a FPC board at the breach and on the exposed conductive wirelayer on one separated glass cover with a conductive glue layer so theFPC board electronically connects to the conductive wire layer via theconductive glue layer.

Therefore, the touch panel of the embodiment of the present invention isthinner, provides better penetrability and higher yield rate and costsless than conventional projected capacitive touch panels.

Other objectives, advantages and novel features of the invention willbecome more apparent from the following detailed description when takenin conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A to 1H are a series of cross sectional side views showingmanufacture of a single-layer projected capacitive touch panel inaccordance with the present invention;

FIG. 2 is a representation of touch sensing circuit layers, insulatingink layers and conductive wire layers on a glass parent board;

FIG. 3 is a top view of a flexible printed circuit board mounted on aglass cover;

FIG. 4 is an explosive view of the single-layer projected capacitivetouch panel in accordance with the present invention; and

FIG. 5 is a cross sectional view of a conventional projected capacitivetouch panel.

DETAILED DESCRIPTION OF THE EMBODIMENTS

A method of manufacturing a single-layer projected capacitive touchpanel in accordance with the present invention comprises steps ofproviding a glass parent board, forming touch sensing circuit layers,forming insulating ink layers having multiple through slots, formingelectric conductors in the through slots, forming conductive wirelayers, forming insulator layers, separating the glass parent board intomultiple glass covers, installing a flexible printed circuit (FPC) boardon one separated glass cover and applying a consolidating glue layer.

With reference to FIG. 1A, in the step of providing a glass parentboard, the glass parent board is divided into multiple glass covers(10), and each glass cover (10) has an operating surface (11) and acircuit surface (12).

With reference to FIG. 1B, in the step of forming touch sensing layers,each touch sensing layer (20) is partially formed on the circuit surface(12) of each glass cover (10) of the glass parent board. With furtherreference to FIG. 2, each touch sensing layer (20) may be formed on acentral zone of the circuit surface (12) of each glass cover (10) andhas multiple edges. Further, the touch sensing circuit layer (20) iscomposed of single-layer touch sensing circuits, such as single-layerindium tin oxide (ITO) circuits.

With reference to FIG. 1C and FIG. 2, in the step of forming insulatingink layers having multiple through slots, each insulating ink layer (30)is formed on and near the edges of each touch sensing circuit layer (20)to partially cover the touch sensing circuit layer (20) so defining atouch zone (21) as uncovered areas of the touch sensing circuit layer(20). Further, each insulating ink layer (30) has multiple through slots(31) corresponding to and exposing the touch sensing circuit layer (20)covered by the insulating ink layer (30). In a preferred embodiment, theinsulating layer (30) is composed of dark ink, and the insulating layer(30) and through slots (31) thereon are formed on the glass cover (10)and partial touch sensing circuit layer (20) by using screen-printingand curing technique. Consequently, other elements subsequently mountedon the insulating ink layer (30) are invisible when viewed from theoperating surface (11) of the glass cover (10).

With reference to FIG. 1D, in the step of forming electric conductors inthe through slots, the electric conductors (32) are filled respectivelyin the through slots (31). In a preferred embodiment, color of eachelectric conductor (32) is similar to the color of the insulating inklayer (30) to avoid people seeing the through slots (32) from theoperating side (11) of the glass cover (10).

With reference to FIG. 1E, in the step of forming conductive wirelayers, the conductive wire layers (40) are formed respectively on theinsulating ink layers of the glass covers (10) on the glass parent boardto contact with the electric conductors (32). Therefore, the conductivewire layers (40) electronically connect respectively to the touchsensing circuit layers (20) via the electric conductors (32). In apreferred embodiment, the conductive wire layers (40) are made of silverglue by using screen printing technique.

With reference to FIG. 1F, in the step of forming insulator layers, theinsulator layers (50) are formed respectively on the conductive wirelayers (40) by using screen printing technique to prevent the conductivewire layers (40) from oxidizing. Further, each insulator layer (50) hasa breach (51) to expose partial conductive wire layer (40). In apreferred embodiment, the insulator layers (50) are made of transparentmaterial.

In the step of separating the glass parent board into multiple glasscovers, the glass parent board is separated into multiple glass covers(10) by a cutting machine.

With reference to FIG. 1G and FIG. 3, in the step of installing a FPCboard on one separated glass cover, the FPC board (70) is attached tothe breach (51) of the insulator layer (50) on the separated glass cover(10) with a conductive glue layer (60). The FPC board (70) iselectronically connected to the conductive wire layer (40) exposedthrough the insulator layer (50) via the conductive glue layer (60). Ina preferred embodiment, the conductive glue layer (60) is made ofanisotropic conductive film (ACF) or anisotropic conductive paste (ACP),and the FPC board (70) is attached to the exposed conductive wire layer(40) with the conductive glue layer (60) by using a heat seal machine.

With reference to FIG. 1H, in the step of applying a consolidating gluelayer, the consolidating glue layer (80) is applied to the FPC board(70) and the glass cover (10) to enhance fastening the FPC board (70)and prevent the FPC board (70) from coming off during other follow-upmanufacturing procedures because of improper installation or dragging.

Therefore, with further reference to FIG. 4, a single-layer projectedcapacitive touch panel in accordance with the present inventionmanufactured by the above-mentioned method comprises a glass cover (10),a touch sensing circuit layer (20), an insulating ink layer (30), aconductive wire layer (40), an insulator layer (50), a conductive gluelayer (60), a FPC board (70) and a consolidating glue layer (80).

The glass cover (10) has an operating surface (11) and a circuit surface(11). The operating surface (11) is for users to touch.

The touch sensing circuit layer (20) is mounted on the circuit surface(12) of the glass cover (10) and has multiple edges.

The insulating ink layer (30) is formed on and covers the edges of thetouch sensing circuit layer (20), and the uncovered touch sensingcircuit layer (20) is defined as a touch zone (21). The insulating inklayer (30) further has multiple through slots (31). The through slots(31) correspond to and expose the touch sensing circuit layer (20)covered by the insulating ink layer (30), and each through slot (31) isfilled with an electric conductor (32).

The conductive wire layer (40) is formed on and covers the insulatingink layer (30) so the conductive wire layer (40) electronically connectsto the touch sensing circuit layer (30) via the electric conductors (32)in the through slots (31).

The insulator layer (50) is formed on and covers the conductive wirelayer (40) and has a breach (51). The breach (51) exposes the partialconductive wire layer (40).

The conductive glue layer (60) is mounted on the breach (51) of theinsulator layer (50) to cover the exposed conductive wire layer (40).

The FPC board (70) is attached to the conductive glue layer (60) to bemounted on the breach (51) of the insulator layer (50) andelectronically connects to the conductive wire layer (40) via theconductive glue layer (60).

The consolidating glue layer (80) is applied to and between the FPCboard (70) and the glass cover (10).

The projected capacitive touch panel in accordance with the embodimentsof the present invention has advantages in the following.

1. Because the touch panel of the present invention only requires asingle glass and the required optical glue layer in the conventionalprojected capacitive touch panel is unnecessary in the touch panel ofthe present invention, the touch panel of the embodiment of the presentinvention is indeed thinner than the conventional projected capacitivetouch panel. Further, the touch panel of the embodiment of the presentinvention also provides better penetrability than the conventionalprojected capacitive touch panel.

2. The touch panel of the embodiment of the present invention does notneed to adhere two glasses so the procedure of adhering glasses is notrequired and the cost for manufacturing the touch panel of theembodiment of the present invention is reduced. Further, manufacturingyield of the touch panel of the embodiment of the present invention isbetter than conventional projected capacitive touch panels. In addition,manufacturing costs of the touch of the embodiment of the presentinvention are also reduced because the touch panel of the embodiment ofthe present invention only requires a single glass.

3. Because the conductive wire layer (40), the insulator layer (50) andthe conductive glue layer (60) are subsequently mounted on theinsulating ink layer (30), they are hidden by the insulating ink layer(30) when viewed from the operating surface (11) of the glass cover(10). Therefore, it is convenient for designers to design a casing on anelectronic device without rims to cover the conductive wire layer (40),the insulator layer (50) and the conductive glue layer (60) in the touchpanel of the embodiment of the present invention.

Even though numerous characteristics and advantages of the presentinvention have been set forth in the foregoing description, togetherwith details of the structure and function of the invention, thedisclosure is illustrative only. Changes may be made in detail,especially in matters of shape, size, and arrangement of parts withinthe principles of the invention to the full extent indicated by thebroad general meaning of the terms in which the appended claims areexpressed.

What is claimed is:
 1. A projected capacitive touch panel, comprising: aglass cover having an operating surface and a circuit surface; a touchsensing circuit layer with multiple edge zones and a touch zone, formedon the circuit surface; an insulating ink layer formed on the edgezones, haying multiple through slots on the edge zones such that thethrough slots correspond to and expose the touch sensing circuit layer,wherein each through slot has an electric conductor therein; and aconductive wire layer formed on the insulating ink layer andelectrically connecting the touch sensing circuit layer via the electricconductors.
 2. The projected capacitive touch panel of claim 1, furthercomprising an insulator layer formed on the conductive wire layer,wherein the insulator layer has a breach to partially expose theconductive wire layer.
 3. The projected capacitive touch panel of claim2, further comprising a conductive glue layer corresponding to thebreach to cover the exposed conductive wire layer.
 4. The projectedcapacitive touch panel of claim 3, further comprising a flexible printedcircuit (FPC) board attached to the conductive glue layer andelectrically connecting the conductive wire layer via the conductiveglue layer.
 5. The projected capacitive touch panel of claim 4, furthercomprising a consolidating glue layer formed between the FPC board andthe glass cover.
 6. The projected capacitive touch panel of claim 5,wherein the consolidating glue layer is located along the outerperiphery of the insulating ink layer.
 7. The projected capacitive touchpanel of claim 3, wherein the conductive glue layer is made ofanisotropic conductive film (ACF) or anisotropic conductive paste (ACP).8. The projected capacitive touch panel of claim 1, wherein color ofeach electric conductor is similar to color of the insulating ink layer.9. The projected capacitive touch panel of claim 1, wherein the touchzone of the touch sensing circuit layer is defined by the touch sensingcircuit layer uncovered by the insulating ink layer.
 10. The projectedcapacitive touch panel of claim 1, wherein the insulating ink layer ismade of dark ink.
 11. The projected capacitive touch panel of claim 1,wherein the conductive wire layer is made of silver glue.
 12. A methodof manufacturing a projected capacitive touch panel comprising steps of:providing a glass cover having an operating surface and a circuitsurface; forming a touch sensing circuit layer on the circuit surface ofthe glass cover, wherein the touch sensing circuit layer has multipleedge zones and a touch zone; forming an insulating ink layers on thetouch sensing circuit layer, with the insulating ink layer formed on theedge zones partially covering touch sensing circuit layer, such that theinsulating ink layer having multiple through slots on the edge zonescorresponds to and exposes the touch sensing circuit layer; formingelectric conductors into the through slots; and forming a conductivewire layer on the insulating ink layer to contact with the electricconductors, thereby electrically connecting the touch sensing circuitlayer via the electric conductors.
 13. The method of claim 12 furthercomprising a step of forming an insulator layer with a breach on theconductive wire layer, wherein the conductive wire layer is partiallyexposed through the breach.
 14. The method of claim 13 furthercomprising a step of mounting a flexible printed circuit (FPC) board onthe exposed conductive wire layer with a conductive glue layer, suchthat the FPC board electrically connects to the conductive wire layervia the conductive glue laver.
 15. The method of claim 14 furthercomprising a step of applying a consolidating glue layer to and betweenthe FPC board and the glass cover after the step of installing the FPChoard.
 16. The method of claim 12, wherein the touch zone of the touchsensing circuit layer is defined by the touch sensing circuit layeruncovered by the insulating ink layer.
 17. A projected capacitive touchpanel, comprising: a glass cover having a first surface and a secondsurface; a touch sensing circuit layer with multiple edge zones and atouch zone, formed on the second surface; an insulating ink layer formedon the edge zones, having multiple through slots on the edge zones suchthat the through slots correspond to and expose the touch sensingcircuit layer, wherein each through slot has an electric conductortherein; and a conductive wire layer formed on the insulating ink layersuch that the conductive wire layer is invisible when viewed through theinsulating ink layer from the first surface of the glass cover, andelectrically connecting the touch sensing circuit layer via the electricconductors.
 18. The projected capacitive touch panel of claim 17,wherein color of each electric conductor is similar to color of theinsulating ink layer.
 19. The projected capacitive touch panel of claim17, wherein the touch zone of the touch sensing circuit layer is definedby the touch sensing circuit layer uncovered by the insulating inklayer.
 20. The projected capacitive touch panel of claim 17, wherein theinsulating ink layer is made of dark ink.